Lamp receptacle

ABSTRACT

A lamp receptacle for use in a lamp socket assembly adapted to receive at least two elongated lamps each of which has two end pins at each end, one side of the receptacle having first and second slots therein, each of the slots being adapted to receive the two end pins at one end of one of the lamps, each of the slots having at least one slot extension connected to the slot and extending to a point spaced from the slot, each of the slot extensions being adapted to receive and hold one of the end pins received in each of the slots when, after the end pins have been inserted into the first and second slots respectively, each lamp is moved in a different direction to place the end pins into the respective slot extensions, and the slot extension of the first slot extends in one direction and the slot extension of the second slot extends in a generally opposite direction. Preferably, the slot extensions are arcuate so that the lamps are rotated in opposite directions to rotate the end pins into the arcuate slot extensions. Also, preferably, end pin retaining means are provided adjacent each slot extension to retain the respective end pins in the slot extension and, if desired, to electrically connect the end pins to a source of electric energy when the end pins of each lamp are inserted in the receptacle. The invention also includes a resilient clip comprising a base portion, a spring arm connected at one end to the base portion, and a detent connected to the other end of the spring arm.

United States Patent [72] Inventors Gerald.|.Shee lulhloGrove; Hans Ege.Des Plaines, both of, III. [21] AppLNo. 776,178 [22] Filed Nov.l5,1968[45] Patented Jnly27,197l [73] Assignee Underwriters Safety Device Co.

ChlcqoJll.

[54] LAMPRECEPTACLE 1 Claim, 10 Drawing Figs.

[52] U.S.Cl 339/53 [51] hLCl. ..I 01r33/08 [50] FieldolSeerch..339/50-57 [56] kelerences Cited UNITED STATES PATENTS 2.137.17411/1938 Marshaws 339/53 2,247,117 6/1941 339/53 2,288,940 7/1942 339/532,436,661 2/1948 Master 339/53 2 ,575,597 11/1951 Semeyn 339/53 PrimaryExaminer-James A. Leppink Assistant Examiner-Joseph H. McGlynnAnomeyGreist, Lockwood, Greenawalt and Dewey ABSTRACT: A lamp receptaclefor use in a lamp socket assembly adapted to receive at least twoelongated lamps each of which has two end pins at each end, one side ofthe receptacle having first and second slots therein, each of the slotsbeing adapted to receive the two end pins at one end of one of thelamps, each of the slots having at least one slot extension connected tothe slot and extending to a point spaced from the slot, each of the slotextensions being adapted to receive and hold one of the end pinsreceived in each of the slots when, after the end pins have beeninserted into the first and second slots respectively, each lamp ismoved in a different direction to place the end pins into the respectiveslot extensions, and the slot extension of the first slot extends in onedirection and the slot extension of the second slot extends in agenerally opposite direction. Preferably, the slot extensions arearcuate so that the lamps are rotated in opposite directions to rotatethe end pins into the arcuate slot extensions. Also, preferably, end pinretaining means are provided adjacent each slot extension to retain therespective end pins in the slot extension and, if desired, toelectrically connect the end pins to a source of electric energy whenthe end pins of each lamp are inserted in the receptacle. The inventionalso includes a resilient clip comprising a base portion, a spring armconnected at one end to the base portion, and a detent connected to theother end of the spring arm.

PATENTEDJULEHSW! I 3.596227 SHEET 1 BF 2 IN VE N TORS GERALD J. SHEAHANS EGE AT ya I PATENTED JUL27 197i SHEET 2 OF 2 INVEN TORS GERALD J.SHEA HANS 65 BY ATT'YS.

LAMP RECEPTACLE BACKGROUND OF THE INVENTION socket assembly, obviatingthe need for a left-hand receptacle and a right-hand receptacle andthereby reducing the cost of the lamp socket assembly.

2. Description of the Prior Art The prior art is replete with lampreceptacles for use in lamp socket assemblies and in particular for usein fluorescent lamp socket assemblies. However; the prior art lampsocket assemblies for mounting elongated or tubular lamps, such asfluorescent lamps, have not always provided a lamp receptacle whichcould be used interchangeably at either end of the assembly. In otherwords, in many prior art lamp socket assemblies a right-hand receptacleand a left-hand receptacle were provided which were similar but notidentical to each other. These rightand left-hand receptacles weredesigned so that an elongated lamp such as a fluorescent lamp can beinserted into the right-hand receptacle and the left-hand receptacle andthen rotated into a fastened position within the lamp socket assembly.

Also, prior art lamp receptacles for use in lamp socket assemblies havenot always been of a simple compact construction whereby the receptacletakes up a minimum of space within the lamp socket assembly.Furthermore, prior art lamp socket assemblies have not always providedalamp receptacle for mounting a fluorescent lamp of the type having twoend pins at each end, at a specific angle, i.e. with at least one endpin of each lamp rotated a specific angular distance when the lamp isinserted in the lamp socket assembly.

SUMMARY OF THE INVENTION One object of this invention is to provide alamp receptacle which is so constructed that two of the lamp receptaclescan be situated at each end, respectively, of a lamp socket assembly formounting both ends, respectively, of two lamps.

Another object of this invention is to provide a lamp socket assemblyhaving two identical lamp receptacles, one at each end of the assembly,for mounting two lamps of the type having two end pins at each endwherein the end pins are received in the receptacles and one lamp isrotated in one direction until the end pins of the lamp are fastenedwithin the lamp receptacles and the other lamp is rotated in theopposite direction until the end pins of the other lamp are fastenedwithin the lamp receptacles.

A further object of this invention is to provide a lamp receptaclehaving end pin retaining means for retaining at least one end pin of anelongated lamp within thelamp receptacle.

A still further object of this invention is to provide resilient clipsfor use in a lamp receptacle all of which clips are formed from anL-shaped strip of metal but with half of the clips formed as mirrorimages of the other halfof the clips.

The invention achieves these and other objects, including those inherenttherein, by providing a lamp receptacle for use in a lamp socketassembly adapted to receive at least two elongated lamps each of whichhas two end pins at each end, one side of the receptacle having firstand second slots therein, each of the slots being adapted toreceive thetwo end pins at one end of one of the lamps, each'of the slots having atleast one slot extension connected to the slot and extending to a pointspaced from the slot,-eachof the slot extensions being adapted toreceive and hold one of the two end pins received in each of the slotswhen, after the lamps have been inserted in the first and second slots,respectively, each lamp is moved in a different direction to placetheend pins into the respective slot extensions, the slot extension ofthe first slot extending in one direction and the slot extension of thesecond slot extending in a generally opposite direction.

The invention achieves other of its objects by providing a resilientclip for retaining an end pin of a lamp in a lamp receptacle, the clipcomprising a base portion, a spring arm connected at one end to the baseportion, and a detent connected to the other end ofthe spring arm.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an exploded perspective viewof a preferred embodiment of the lamp receptacle of this invention;

FIG. 2 is a front elevational view of the lamp receptacle shown in FIG.1;

FIG. 3 is a back elevational view of the housing of the lamp receptacleshown in FIG. 1;

FIG. 4 is a front elevational view of the terminal block of the lampreceptacle shown in FIG. 1;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 2';

FIG. 6 is a sectional view taken along lines 66 of FIG. 4;

FIG. 7 is an enlarged perspective view of one of the resilient clipsshown in FIG. 1;

FIG. 8 is an enlarged plan view of an L-shaped strip of metal which isformed into the resilient clip shown in FIG. 7;

FIG. 9 is a perspective view of the lampreceptacle shown'in FIG. 1showing portions of two elongated lamps in phantom lines;

FIG. 10 is a front elevational view of the lamp receptacle shown in FIG.1 showing portions of the end pins oftwo lamps received in the arcuateslot extensions.

A fluorescent lamp receptacle is generally indicated at 10 in FIG. 1.The receptacle 10 comprises a housing 12 and a terminal block 14, whichare preferably made from an insulating material such as a moldableplastic material. Four resilient spring clips l6, 17, 18 and 19 aresecured to the front face 20 of the terminal block 14. In theillustrated embodiment, the terminal block 14 has four notches 22, 23,24 and 25which receive respectively an attaching flange of each of theclips l6, 17, 18 and 19. These notches 2225 are formed in andtransversely of the front face 20 parallel to each other. One pair 22,2-3 of the notches 22-25 are disposed on one side of the front face 20and the other pair 23, 24 of the notches'2225ar e disposed on the otherside of the front face 20, as shown in FIGS. 1 and 4, with a centrallydisposed locating surface 28 separating the two pairs of notches. Ifdesired, the locating surface 28-can be spaced from the front face 20.

The housing 12 comprises two end walls 30 and 32 and three sidewalls 34,35 and 36, as shown in FIGS. 1 and 3. In the embodiment illustrated, thesidewall or side 35 can be considered the front sidewall while thesidewalls 34 and 36 can be considered as the top and bottom wallsrespectively. The side opposite the sidewall 35 is open to receive theterminal block 14. Inside of the housing 12 is a raised portion 38,which is disposed substantially midway between the end walls 30 and 32and which extends from thefront sidewall 35 toward the open side of thehousing 12, as shown in FIGS. 3 and 5. When the housing 12 and theterminal block 14 are assembled, the locating surface 28 engage theinner surface 39 on the raised portion 38. If desired, an adhesive canbe disposed between the surfaces 28 and 39 for securing the housing 12to the terminal block 14. In some situations, use of an adhesive tosecure the housing 12 to the terminal block 14 will simplify assembly ofthe lamp receptacle 10 and also reduce the cost of manufacturing thelamp receptacle 10.

In the embodiment illustrated in FIG. 5, a rivet 40 is used to fastenthe housing 12 to the terminal block 14. For this pur In some lampsocket assemblies, when a rivet, screw (and nut) or drive pin is used(particularly a screw) to fasten the housing 12 to the terminal block14, the housing 12 can be removed from the terminal block 14 be removingthe rivet, screw or drive pin, to allow for repair or replacement ofparts, (e.g. the clips 16-19) in the lamp receptacle 10. In these lampsocket assemblies the receptacle 10 is mounted in the assembly bysecuring the back side or surface 48 (FIGS. and 6) of the terminal block14 to the frame of the lamp socket assembly (not shown) by an adhesiveor other suitable fastening means. To facilitate use of an adhesive backsurface 48 is preferably a planar surface.

In one embodiment of the invention, the lamp receptacle 10 is secured toan L-shaped mounting bracket 49, shown in phantom lines in FIG. 5. Thebracket 49 includes two frame sections 50 and 51. In FIG. 5, the framesection 50 is disposed generally horizontally and the frame section 51is disposed generally vertically. The lamp receptacle 10 is positionedon the bracket 49 with the bottom wall 36 resting on the frame section50 and the back surface 48 flush against the frame sec- .tion 51. Inthis embodiment, a longer rivet 40a, shown in phantom lines, is insertedthrough the bores 41 and 42 and through a hole in the frame section 51,and then staked over at 470 to secure both the housing 12 and theterminal block 14 to the bracket 49. 1

Each one of the clips 16, 17, 18 and 19 is secured in a respective notch22, 23, 24, or 25 by a drive pin 52, 53, 54 and 55, as shown in FIGS. 1,4 and 6. Each one of the clips 16, 17, 18 and 19 is generally S-shaped.All of the clips are formed from an L-shaped piece of metal 56 (FIG. 8).However, some of the clips are formed with the attaching flange, such asflange 57 of clip 18, extending on one side of the clip 18, while otherof the clips have the attaching flange, such as flange 58 o'f clip 17extending on the other side of the clip 17. In other words, some of theclips are mirror images of the other clips, i.e. the clips 16 and "aremirrorimages of the clips 18 and 19. Since each of the clips areessentially the same, only one clip, clip 17, will be described indetail.

As shown in FIG. 7, the clip 17 comprises an attaching flange 58 havingan opening 59 therein for receiving drive pin 53 when the clip 17is'mounted in the notch 23 in the terminal block 14. The basiccomponents of the clip 17 are the attaching flange 58, an L-shaped baseor support portion 60 including two leg sections 61 and 62, a spring arm53 and a detent or detent portion 64. The attaching flange 58 isconnected to (i.e. integral with) the leg section 61 while one end ofthe spring arm 63 is connected to (i.e. integral with) the leg section62. The detent 64 is connected to the other end of the spring arm 63.Preferably, the detent 64 is a rounded extension of the arm 63 formed bybending over the other end of the arm 63.

It will be readily understood that the forming of the clips 16, 17, 18and 19 from identical L-shaped strips of metal will facilitate themanufacture of the lamp receptacle 10 as well as minimize the cost forconstructing the clips 16, 17, 18 and 19.

. Also, as will be more fully explained below, each of the clips canserve the dual function of (a) holding an end pin of an elongatedtubular lamp within the lamp receptacle 10 and, (b) providing anelectrical connection to the end pin, while allowing the pins to beinserted through the top wall 34, i.e. the clips 16, 17, 18 and 19 donot interfere with the introduction or insertion of the end pins of theelongated or tubular lamps through-the top wall 34 into the lampreceptacle 10.

, In the embodiment of the invention illustrated in FIGS. 1, 4

v and 5, wire conductors 72, 73, 74 and 75 are connected by means oflugs76, 77,78 and 79 to each one of the clips 16, 17,

18 and 19. The lugs 76, 77, 78 and 79 can be of any known type such as abifurcated lug or an eyelet-type lug. Each of the lugs 76-79 is disposedbeneath the respective attaching flange 57 or 58 ofeach of the clips16--19 and than secured between the attaching flanges 57 or 58 and therespective respective drive pins 52, 53, 54 and 55.

Passage means for the entry or insertion of the wire conductors 72, 73,74 and 75 into the lamp receptacle 10 is provided in the form ofopenings 81, 82, 83 and 84 (FIGS. 2 and 3) in the front sidewall 35 ofthe housing 12. It is to be appreciated that these openings can beformed in the end walls 30 or 31 or in the other sidewalls 34 and 36 ofthe housing 12. On the other hand, a different type of passage means inthe form of one or two larger openings can be provided in either thehousing 12 or the terminal block 14 for entry of the wire conductors 72,73, 74 and 75 into the lamp receptacle 10.

In some applications, such as, for example, where only two of the clips16-19 serve as electric contacts, less than four conductors will beneeded for the two lamps inserted in the lamp receptacle 10, and lessthan four openings will be needed. In these applications another form ofpassage means may be provided.

Returning now to the construction of the housing 12, the first andsecond slots 91 and 92 are provided in the sidewall 35 of the housing 12as shown in FIGS. 1, 2 and 3. Preferably, the slots 91 and 92 areparallel to each other. However, the slots 91 and 92 need not beparallel. It is essential though, that they be mirror images of eachother so that two identical receptacles 10 can be used at each end of adouble lamp socket assembly. Third and fourth parallel slots 93 and 94(FIG. 1) are formed in the top sidewall 34 of the housing 12. Thesidewalls 34 and 35 are adjacent one another and form an edge 96therebetween. The first and second slots 91 and 92 extend to the edge96. The third and fourth parallel slots 93 and 94 also extend to theedge 96 to mate or connect with the first and second slots 91 and 92. vI

In the embodiment illustrated, the first slot 91 is provided with a pairof arcuate slot extensions 97 and 98. Likewise, the second slot 92 isprovided with a pair of arcuate slot extensions 99 and 100.

The slots 91 and 92 are each designed to receive the two end pins 101aand 101b or 1010 and 101d of a conventional fluorescent lamp 102a orl02b shown in phantom lines in FIGS. 9 and 10. The slots are alsodesigned so that electrical contact means (e.g. clips 16-19) can contactthe end pins for connecting a heating element or a filament at each endof each fluorescent lamp 102a and l02b to a source of electric energyand also for connecting an electric potential across each lamp 102a and10212.

An important aspect of the invention is that one pair of the arcuateslot extensions 97, 98 extend in one rotational direction and the otherpair of arcuate slot extensions extend in the opposite rotationaldirection, with each of the arcuate slot extensions being connected to arespective slot 91 or 92 and extending to a point spaced from therespective slot 91 or' 92, whereby the end pins 101a, 101b of one lampreceived in the first slot 91 are rotated in one direction to a fastenedposition and the end pins 101C, 101d of the other lamp 102b received inthe second slot 92 are rotated in the opposite direction to a fastenedposition.

In some applications one arcuate slot extension of each pair of arcuateslot extensions can be omitted, e.g. arcuate slot extensions 98, or 97,99 can be omitted. Such a construction might be preferred where heatingelements are not utilized in the fluorescent lamp and only one end pinat each end of the fluorescent lamp is needed for placing an electricpotential across the lamp.

With the arcuate slot extensions formed in the manner stated, each lampreceptacle 10, when facing another receptacle 10, will be a mirror imageof the other receptacle 10. Thus, in a lamp socket assembly two lampreceptacles 10 are mounted in spaced apart relationship with sidewall 35on one lamp receptacle 10 facing sidewall 35 on the other lamp lampreceptacle and the end pins (not shown) at the other end of that lamp102a being received in the second slot 92 in the slot 92 in the onereceptacle and the end pins (not shown) at I the other end of the secondlamp are received in the first slot 91 in the other lamp receptacle (notshown). After the first lamp is inserted in the respective first andsecond slots 91, 92 of the two lamp receptacles 10, it is rotated in onedirection to place the end pins at each end of the lamp into therespective arcuate slot extension 97 and 98 in the one lamp receptacleand the respective arcuate slot extensions 99 and 100 in the otherlampreceptacle 10. On the other hand, t he second lamp is rotated in theother or opposite rotational direction to place the end pins at each endof the second lamp intothe respective arcuate slot extensions 99 and 100in the onelamp receptacle and the respective arcuate slot extensions 97and 98 in the other lamp receptacle respectively. i

The third and fourth slots 93, 94 facilitate the insertion of the twolamps 102a and 102!) into the lamp receptacle. When inserting the onelamp 102a into the lamp receptacle, the two end pins 101a, 1011: arefirst inserted into the third slot laterally of, along and parallel tothe third slot and then into the first slot, transversely of the firstslot until the two end pins 101a, 1011: of the one lamp 1020 are alignedwith the respective arcuate slot extensions 97, 98, whereupon the onelamp 102a is rotated in one rotational direction to place at least oneof the two end pins 1010 or 1011: of the lamp 102 a into one of thearcuate slot extensions 97 or 98. In like manner the other lamp 102b isfirst inserted into the fourth slot 94 and then into the second slot 92.When the end pins 101c and 101d are aligned with the slot extensions 99and 100, the other lamp l02b is rotated in the other or oppositerotational direction to place at least one of the two end pins 101c and101d into one of the arcuate slot extensions 99 or 100. I

As shown in FlG. 2, each of the clips 16, 17, 18 and 19 is situatedadjacent one of the arcuate slot extensions 97-100 so that the detentportion 64 of each of the clips extends into the path of one of the endpins 1010, 101b, 1010 and 101d of the lamps 102a and 1021; when they arerotated into the arcu} ate slot extensions 97, 98, 99 and 100. In thisway, the resilient spring clips 3t3-19 provide resilient holding orretaining means for engaging and retaining the respective end pins ofthe respective lamps in the arcuate slot extensions 97100- when the pinsare inserted or placed into the arcuate slot extensions 97-100. As anend pin engages the detent portion 64, the spring arm 63 allows thedetent portion 64 to be. moved out of the path of the end pin under thepressure of the end pin. After an end pin has been moved past detentportion 64, the detent portion 64 is returned to its previous positionby spring arm 63. The spring arms 63 have sufficient stiffnessorrigidity to hold or retain the end pins of the lamps in the respectivearcuate slot extensions 97- 100 and yet have sufficient resiliency topermit the end pins to be easily moved in and out of the respectivearcuate slot extensions97- 100 past the detent portions 64.

Each arcuate slot extension 97, 98', 99 and 100. is provided.

with a rounded end portion 103, 104, 105 and 106 against which therespective end pins of each lamp are seated. The detent portions 64extend into the path of the end pins received in the arcuate slotextensions 97100, and-are arranged or.

aligned so as to snugly and resiliently hold the respective end pins ofeach lamp 102a and 102b against the rounded end portions 103, 104, 105and 106 of the arcuate slot extensions 97, 98, 99 and 100. The arcuateslot extensions 97- 100' and the rounded end portions 103 106 thereofare formed so that the lamps, mounted in the first and second slots 91and 92 respcc? tively, are rotated in opposite directions the sameangular distance before the end pins of each lamp 102a and 102b are,

seated against the respective rounded end portion 103-106 of therespective arcuate slot extension 971'00.

In the embodiment shown in FIG. 2, the center point of the curve of eachrounded extension 103 and 104,. or 105 and point situated approximatelyon the centerline 112 of the.

second slot 92. With the arcuate slot extensions 97100 constructed inthis manner the angle A between a horizontal datum line 114 and the line109 passing through the centers of the curves of the rounded endportions 103, and 104 is equal to the angle B between the horizontaldatum line 114 and the line 1 10 passing through the centers of thecurves of the rounded end portions and 106.

From the foregoing specification those skilled in the art willappreciate that this invention, described above and illustrated in theaccompanying drawings, provides a simple and compact lamp receptacle anda simple resilient clip which can be easily and inexpensivelymanufactured. It is also tobe appreciated that two of the lampreceptacles described and illustrated, can be easily secured into adouble lamp socket assembly by an adhesive, by a'rivet, or by a screwand nut. Furthermor'e,the' lamp receptacle can be formed with aplurality of even numbered slots similar to slots 91 and 92 e.g.two'four, sim-eight; etc;, with the first slot being a mirror image ofthe secondslot, the third slot being a mirror image of the fourth slot,etc. Such modified receptacles then can be usedat each end of a multiple(even numbered) lamp socket assembly.

1 claim:

1. A lamp socket assembly which is-adapted to receive at least twoelongated lamps each having two end pins at each end,,said assemblyincluding two identical, spaced apart lamp receptacles with each of saidlamp receptacles comprising:

a generally rectangular box-shaped housingmade of an insulatingmaterial;

a first elongated side of said housing having at-least one set of firstand second'main slots therein which are mirror images of each other;

each main slot defining an unobstructed end pin receiving channel forreceiving the two end pins at one end'of one of said lamps; i

a second elongated side of said housing adjacent said first to a pointspaced from the centerline of said main slot and i a second arcuate slotextension communicating with said main slot at a point spaced from saidinnerend'of said main slot and extending laterally of said-main slot toa point spaced from said centerline of said main slot; each one of saidarcuate slot extensions having an end portion against which a. lamp endpin can be seated; said two arcuate slotextensions which communicatewith said' first main slot extending from opposite sides of saidcenterline of said first main slot in one arcuate direction apredetermined angular extent about a center point situated approximatelyon said centerline of said first main slot and said two arcuate slotextensions which communicate with said second main slot extending fromopposite sides of said centerline of said second main slot in anopposite arcuate direction the same'predetermined angular extent about acenter point situated-approximately on said centerline of said secondmainslot, whereby, after the end portion of one of said slot extensionsof said first or second main slot;

a generally rectangular terminal block made of an insulating materialand secured to said housing opposite said first elongated side of saidhousing;

at least four, electrically conductive, resilient contacts fixed to saidterminal block at spaced apart locations thereon and extending fromsaidterminal block into said housing;

means for connecting each of said contacts to a source of electricpotential;

each of said contacts including a base portion fixed to said terminalblock, a spring arm connected at one end to said base portion, and adetent portion connected to the other end of said spring arm;

said terminal block having means for engaging said base portion of eachof said contacts to prevent turning of each contact in a directiongenerally parallel to said terminal block while permitting flexing ofsaid spring arm of each of said contacts in said direction generallyparallel to said terminal block;

each one of said detent portions extending outwardly from said terminalblock and laterally toward, but not into, a plane containing thecenterline of one of said.para llel slots and the centerline of one ofsaid main slots. "a 'nd being normally positioned behind one of saidarcuate slot extensions and in the path of an end pin received in saidone of said arcuate slot extensions; and, 5

each of said detent portions serving as a retaining clip which isdeflected in said direction generally parallel to said ter-' minal blockby an end pin moving into said one of said arcuate slot extensions andwhich returns to its normal position, after said pin is moved past saiddetent portion, for holding said end pin against the end portion of saidone f said arcuate slot extensions.

1. A lamp socket assembly which is adapted to receive at least twoelongated lamps each having two end pins at each end, said assemblyincluding two identical, spaced apart lamp receptacles with each of saidlamp receptacles comprising: a generally rectangular box-shaped housingmade of an insulating material; a first elongated side of said housinghaving at least one set of first and second main slots therein which aremirror images of each other; each main slot defining an unobstructed endpin receiving channel for receiving the two end pins at one end of oneof said lamps; a second elongated side of said housing adjacent saidfirst elongated side having at least one set of parallel slots thereinwhich individually connect with a respective one of said first or secondmain slots to permit insertion of said lamp end pins into saidreceptacle in a direction transverse to the longitudinal axes of saidend pins; each main slot having a first arcuate slot extensioncommunicating with the inner end of said main slot and extendinglaterally of said main slot from said inner end thereof to a pointspaced from the centerline of said main slot and a second arcuate slotextension communicating with said main slot at a point spaced from saidinner end of said main slot and extending laterally of said main slot toa point spaced from said centerline of said main slot; each one of saidarcuate slot extensions having an end portion against which a lamp endpin can be seated; said two arcuate slot extensions which communicatewith said first main slot extending from opposite sides of saidcenterline of said first main slot in one arcuate direction apredetermined angular extent about a center point situated approximatelyon said centerline of said first main slot and said two arcuate slotextensions which communicate with said second main slot extending fromopposite sides of said centerline of said second main slot in anopposite arcuate direction the same predetermined angular extent about acenter point situated approximately on said centerline of said secondmain slot, whereby, after each pair of end pins is received in one ofsaid main slots, said lamps can be rotated the same angular extent butin opposite arcuate directions to place each end pin against the endportion of one of said slot extensions of said first or second mainslot; a generally rectangular terminal block made of an insulatingmaterial and secured to said housing opposite said first elongated sideof said housing; at least four, electrically conductive, resilientcontacts fixed to said terminal block at spaced apart locations thereonand extending from said terminal block into said housing; means forconnecting each of said contacts to a source of electric potential; eachof said contacts including a base pOrtion fixed to said terminal block,a spring arm connected at one end to said base portion, and a detentportion connected to the other end of said spring arm; said terminalblock having means for engaging said base portion of each of saidcontacts to prevent turning of each contact in a direction generallyparallel to said terminal block while permitting flexing of said springarm of each of said contacts in said direction generally parallel tosaid terminal block; each one of said detent portions extendingoutwardly from said terminal block and laterally toward, but not into, aplane containing the centerline of one of said parallel slots and thecenterline of one of said main slots, and being normally positionedbehind one of said arcuate slot extensions and in the path of an end pinreceived in said one of said arcuate slot extensions; and, each of saiddetent portions serving as a retaining clip which is deflected in saiddirection generally parallel to said terminal block by an end pin movinginto said one of said arcuate slot extensions and which returns to itsnormal position, after said pin is moved past said detent portion, forholding said end pin against the end portion of said one of said arcuateslot extensions.